#!/usr/bin/env bash
###############################################################################
# backlink.nb-plugin
#
# Add backlinks to notes.
#
# Depends on note-link-janitor:
#   https://github.com/andymatuschak/note-link-janitor
#
# Install with:
#   nb plugin install https://github.com/xwmx/nb/blob/master/plugins/backlink.nb-plugin
#
# https://github.com/xwmx/nb
###############################################################################

# Add the new subcommand name with `_subcommands add <name>`.
_subcommands add "backlink"

# Define help and usage text with `_subcommands describe <subcommand> <usage>`.
_subcommands describe "backlink" <<HEREDOC
Usage:
  nb backlink [--force]

Description:
  Add backlinks to notes. Crawl notes in a notebook for [[wiki-style links]]
  and append a "Backlinks" section to each linked file that lists passages
  referencing the note.

  To link to a note from within another note, surround the title of the
  target note in double square brackets:

      Example with link to [[Target Note Title]] in content.

  Depends on note-link-janitor:
    https://github.com/andymatuschak/note-link-janitor

    Requirement: every note in the notebook must have a title.
HEREDOC

# Define the subcommand as a function, named with a leading underscore.
_backlink() {
  if ! hash "note-link-janitor" 2>/dev/null
  then
    printf "\
note-link-janitor required:
  https://github.com/andymatuschak/note-link-janitor\\n" 1>&2
    exit 1
  fi

  if ! [[ "${1:-}" == "--force" ]]
  then
    printf "Adding backlinks to notes. This could update multiple files.\\n"

    while true
    do
      IFS='' read -r -e -d $'\n' -p "Proceed? [y/N] " __yn
      case ${__yn} in
        [Yy]*)
          break
          ;;
        *)
          printf "Exiting...\\n"
          exit 0
          ;;
      esac
    done
  fi

  local _notebook_path
  _notebook_path="$(_notebooks current --path)"

  note-link-janitor "${_notebook_path}"

  if [[ -n "$(_git status --porcelain)" ]]
  then
    _git checkpoint "[nb] Backlinked"
    printf "Backlinked!\\n"
  else
    printf "No new links found.\\n"
  fi
}
